Not Applicable.
This invention pertains to clamping of pipes with use of a chain vise. The chain vise is a well known tool consisting of a V-shaped cradle on which a pipe rests, and a roller chain of links used to overlie the pipe and be tightened. When so clamped, the pipe may rotate as the chain is tightened about the pipe. Since pipe to be welded is oriented specifically to allow an accurate weld, rotation during tightening is an undesirable result, resulting in the necessity to release the vise, position the pipe, and retighten the chain vise.
The present invention is a tool to reduce the rotational force on a pipe to be held in a chain vise. The invention comprises a curvilinear or inverted V-shaped base which saddles the pipe to be held. A U-shaped frame is mounted to the base such that one or more rollers may be mounted between the opposing sides of the U-shaped frame. The rollers provide a bearing surface for the chain of the chain vise, allowing the chain to be tensioned without applying torque to the pipe to be held.
In an alternate embodiment a pair of the tools are joined by a spacing handle such that the tools may be rested upon the upper surface of a large pipe, with the chain of the chain vise passing over the roller of each of the tools.
It is an object of the invention to provide an improved chain vise which effectively clamps a pipe while reducing the tendency of the held pipe to rotate as the vise chain is tightened.
It is a further object of the invention to provide an inexpensive yet effective tool to be used with an existing chain vise to avoid rotation of a pipe held by the device to rotate as the chain is tightened.
It is another object of the invention to make the welding of pipe sections more efficient by providing a tool which eliminates rotational force on a pipe held in a chain vise.
These and other objects of the invention will become apparent from examination of the description and claims which follow.